1-(5-Isoquinolinesulfonyl)homopiperazine hydrochloride (hereinafter referred to as “fasudil hydrochloride”) having an excellent vasodilatation effect is commercially available under the trademark of “Eril Inj.” (manufactured by Asahi Kasei Pharma Corp.) and clinically used as an injection preparation for improving cerebrovascular spasm after a subarachnoid bleeding operation and an accompanying brain ischemia symptom (Patent Document 1).
Fasudil hydrochloride crystals are known to include crystals not containing crystal water (hereinafter referred to as “fasudil hydrochloride anhydride”) and crystals containing crystal water (hereinafter referred to as “fasudil hydrochloride hydrate”) (Patent Document 2).
An aqueous solution of fasudil hydrochloride is known to produce decomposition products by irradiation of light. To reduce generation of the decomposition products by light irradiation, injections and the like containing an aqueous solution of fasudil hydrochloride are supplied to the market in a form shielded from light, e.g. filled into a brown container or the like.
An aqueous solution injection of fasudil hydrochloride filled into a colored container or a container coated with a light-shielding coating of which the transmission rate of tight particularly with a wavelength of 350 nm is 10% or less has been known (Parent Document 3).
[Patent Document 1] JP-B5-3851
[Patent Document 2] WO 97/02260
[Patent Document 3] JP-A-9-24085